Central Boiler CLASSIC Owner's Manual page 22

WATER TO WATER HEAT TRANSFER SYSTEM
USING A WRAPAROUND HEAT EXCHANGER
Another option for installing the water-to-water heat
exchanger for increased heat transfer is illustrated in Fig.
26. This wraparound installation allows circulation
continuously through the heat exchanger, maintaining the
maximum exchanger temperature in the existing boiler. Note
the water flows in opposite directions.
22
With this type of installation, the exchange temperature
may be more than 165° F and may eliminate the need for
additional baseboard heaters or other added heat exchanger
as illustrated.
When installing water-to-water heat exchangers, be sure
to flush any rust particles or sediments out of existing boiler.
A 009 Taco pump must be used for the outdoor system and
Anti-Sludge Conditioner (p/n 166) also must be added in
the outdoor wood furnace.
Fig. 28
Section 3 - Furnace Installation